1. Field of the Invention
The present invention relates to a motor controlling circuit, a motor driving device, and a method of driving a motor.
2. Description of the Related Art
A brushless direct current (BLDC) motor generally refers to a DC motor in which a function of conducting current or adjusting a current direction is adjusted by using a non-contact position detector and a semiconductor device rather than using a mechanical contact such as a brush, a commutator, or the like, in the DC motor.
Generally, a speed of a motor, of which a speed is controllable, may be controlled by adjusting a duty value of a pulse width modulation (PWM) signal. The duty value of the pulse width modulation signal may be determined according to a ratio between a turn-on time at which the signal has a high value in a single signal period and a turn-off time at which the signal has a low value in a single signal period, and a rotational speed of the motor may be in proportion to the duty value of the pulse width modulation signal.
In the case of the BLDC motor, the rotation of the motor is controlled according to a hall signal of which a level is changed according to polarity, and motor controlling signals are generated by detecting a falling edge at which the level of the hall signal is changed from high to low and a rising edge at which the level of the hall signal is changed from low to high.
Since driving of the motor is controlled according to the hall signal, in the case in which noise is generated in the hall signal, erroneous motor controlling signals may be generated, such that the motor may rotate in reverse.
In addition, in the case in which the level of the hall signal rises from low to high, impulse signals may be generated several times until the hall signal has a stabilized high level. Here, in controlling the driving of the motor, in the case in which the motor controlling signals are generated by detecting both of the rising and falling edges of each impulse signal generated before a high level is stabilized, motor driving efficiency may be deteriorated.